The general use of either rods or plates fixed to the vertebrae above and below a defect such as a fracture, ruptured disc, tumor, or deformity, is known, especially in the thoracic and thoracolumbar spine. The system disclosed in U.S. Pat. No. 5,603,714 uses rods to connect screws threaded into each vertebra spanning the defect. The advantage of a rod-based system is its flexibility to accommodate different indications using the same basic components. A disadvantage of rod-based systems is in the distance the device extends outwardly from the vertebrae, potentially affecting the surrounding muscle and causing pain to the patient.
A plate-based system can have a lower profile than a rod-based system. The application technique for a plate-based system is generally more straightforward than a rod-based system. Most plate-based systems include a plate sized to span one or more disc spaces, and screws or bolts to fasten the plate to the vertebrae. Various plate-based systems are disclosed in U.S. Pat. Nos. 5,324,290, 6,206,882, 6,342,055, and 6,755,833.